+static void setup_pcid(struct cpuinfo_x86 *c)
+{
+ if (cpu_has(c, X86_FEATURE_PCID)) {
+ if (IS_ENABLED(CONFIG_X86_64) &&
+ (cpu_has(c, X86_FEATURE_PGE) || kaiser_enabled)) {
+ /*
+ * Regardless of whether PCID is enumerated, the
+ * SDM says that it can't be enabled in 32-bit mode.
+ */
+ set_in_cr4(X86_CR4_PCIDE);
+ /*
+ * INVPCID has two "groups" of types:
+ * 1/2: Invalidate an individual address
+ * 3/4: Invalidate all contexts
+ *
+ * 1/2 take a PCID, but 3/4 do not. So, 3/4
+ * ignore the PCID argument in the descriptor.
+ * But, we have to be careful not to call 1/2
+ * with an actual non-zero PCID in them before
+ * we do the above set_in_cr4().
+ */
+ if (cpu_has(c, X86_FEATURE_INVPCID))
+ set_cpu_cap(c, X86_FEATURE_INVPCID_SINGLE);
+ } else {
+ /*
+ * flush_tlb_all(), as currently implemented, won't
+ * work if PCID is on but PGE is not. Since that
+ * combination doesn't exist on real hardware, there's
+ * no reason to try to fully support it, but it's
+ * polite to avoid corrupting data if we're on
+ * an improperly configured VM.
+ */
+ clear_cpu_cap(c, X86_FEATURE_PCID);
+ }
+ }
+ kaiser_setup_pcid();
+}
+